1.  Were you in Buenos Aires yesterday? (Buenos Aires) 

Yes, I was.

2.  Was she in El Salvador last Saturday? (Chile)

No, she wasn't.

3.  Was Pamela a teacher in 1999? (a policeman))

No, she wasn't.

4.  Were Lisa and Michael in Bolivia last year? (Bolivia)

Yes, they were.

5.  Were they my teachers in 1990? (Paul's teachers)

No, they weren't.